From Bruce, N1RX comes the following:

The Olimex MSP430-JTAG works fine for reprogramming the ATS-3. I have 
used it sucessfully. It is available from Spark-Fun electronics. Search
for "MSP-JTAG" at the Spark Fun website, it should be about $15.

It is terminated in a standard 14-pin female dual-inline ribbon 
connector. The connections from this connector to the 7-pin header on 
the ATS-3 are as follows:


When using Olimex or other JTAG device:
-----------------------------------------
JTAG device pinout to ATS3 MSP430

JTAG			ATS3 HDR
PIN	SIGNAL	PIN
	
1	P1.7-TDO	7
3	P1.6-TDI	6
5	P1.5-TMS	5
7	P1.4-TCK	4
8	TST		2
9	GND		1
11	RST		3

The programming header on the ATS-3 is above the MPU chip, numbered 1-7 
from left to right, when holding the board with the phones/pwr/key 
sockets to the left, and the antenna connector on the right.

Hope this helps...
-Bruce N1RX

_____________________________________________________________
And this is how the pins are oriented on the Olimex cable:
_____________________________________________________________

The red tracer wire indicated which end of the ribbon is pin 1, and the arrow 
on the connector shows the same. Just remember that the pins are numbered
with all the odd numbers down one row, and all the even down the other.
So graphically, looking into the end of the female connector on the
cable, with the arrow at the top right, the pins are numbered as so:

2 1
4 3
6 5
8 7
10 9
12 11
14 13

Hope this helps. Let me know if you need any further info.
73, Bruce Beford N1RX